Narrator Confusion?

9.  Though Othello is the protagonist, the majority of soliloquies and asides are given by Iago.  Why?

"I hate the Moor, and it is thought abroad that 'twixt my sheets he's done my office.  I know not if 't be true, but I for mere suspicion in that kind will do as if for surety" I.iii.366-370.

We brought this up briefly in class, but as I read Act 3 tonight and thought more about Acts 1-2, it started to make more sense to me why this story is so confusing to me.  I had confused my protagonist!   With the story being told mainly from the evil plotting of Iago, it made me grow fond of him in the first Acts.  He mad himself sound so kind and honest and I never got the sense that he was an evil mastermind until we began to hear things more from Cassio's point of view in the third Act.

However, I want to base this analysis on the first Act.  In I.i.8-33, Iago actually made a very strong argument for himself as to why he should have been put in Cassio's position.  Had Othello told us why Cassio was put in this position, then not only would we not have been given suspense from a lack of the truth, but there would be zero conflict in this story.  We would have been given a history report in Act 1 and the entire play would be over, but by having an antagonist drive the story, it gives the reader a conflicting emotion toward who to support.  Since the reader mainly hears why Iago does what he does, it makes it sound like he has just reasons for his actions, but later Acts clearly show that he is a greedy little... man... who cannot be trusted.  Not going to lie, I feel like this story would be a lot better if it was in modern language, but from what I understand of this, I am totally on team Iago.  This probably also stems from the fact that he has those soliloquies that give us some quality one on one time to really get to the know the guy.  All that I know about everyone else is that they are fools.